nanog mailing list archives

Re: Juniper BGP Convergence Time


From: Mike Hammett <nanog () ics-il net>
Date: Thu, 17 May 2018 07:55:20 -0500 (CDT)

Just be aware of the impact a default route can have on your infrastructure, such as uRPF no longer works as expected 
as everything has a valid route. 




----- 
Mike Hammett 
Intelligent Computing Solutions 
http://www.ics-il.com 

Midwest-IX 
http://www.midwest-ix.com 

----- Original Message -----

From: "Adam Kajtar" <akajtar () wadsworthcity org> 
To: erich () gotfusion net 
Cc: nanog () nanog org 
Sent: Wednesday, May 16, 2018 9:32:27 AM 
Subject: Re: Juniper BGP Convergence Time 

Erich, 

Good Idea. I can't believe I didn't think of that earlier. Simple and 
effective. I will go ahead and request the defaults from my ISP and update 
the thread of the findings. 

Thanks! 

On Wed, May 16, 2018 at 10:03 AM Kaiser, Erich <erich () gotfusion net> wrote: 

A last resort route (default route) could still be good to take from your 
ISP(s) even if you still do full routes, as the propagation is happening on 
the internet side, you should at least have a path inbound through the 
other provider. The default route at least would send the traffic out if 
it does not see the route locally. Just an idea. 



On Wed, May 16, 2018 at 8:22 AM, Adam Kajtar <akajtar () wadsworthcity org> 
wrote: 

I could use static routes but I noticed since I moved to full routes I 
have had a lot fewer customer complaints about latency(especially when it 
comes to Voice and VPN traffic). 

I wasn't using per-packet load balancing. I believe juniper default is 
per 
IP. 

My timers are as follows 
Active Holdtime: 90 
Keepalive Interval: 30 

Would I be correct in thinking I need to contact my ISP to lower these 
values? 

An interesting note is when I had both ISPs connected into a single MX104 
the failover was just a few seconds. 

Thanks again. 



On Tue, May 15, 2018 at 8:42 PM Ben Cannon <ben () 6by7 net> wrote: 

Have you checked your timeouts ? 

-Ben 

On May 15, 2018, at 4:09 PM, Kaiser, Erich <erich () gotfusion net> 
wrote: 

Do you need full routes? What about just a default route from BGP? 

Erich Kaiser 
The Fusion Network 
erich () gotfusion net 
Office: 815-570-3101 




On Tue, May 15, 2018 at 5:38 PM, Aaron Gould <aaron1 () gvtc com> 
wrote: 

You sure it doesn't have something to do with 60 seconds * 3 = 180 
secs of 
BGP neighbor Time out before it believes neighbor is dead and remove 
routes 
to that neighbor? 

Aaron 

On May 15, 2018, at 9:10 AM, Adam Kajtar <akajtar () wadsworthcity org 

wrote: 

Hello: 

I'm running two Juniper MX104s. Each MX has 1 ISP connected running 
BGP(full routes). iBGP is running between the routers via a two port 
20G 
lag. When one of the ISPs fails, it can take upwards of 2 minutes 
for 
traffic to start flowing correctly. The router has the correct route 
in 
the 
routing table, but it doesn't install it in the forwarding table for 
the 
full two mins. 

I have a few questions if anyone could answer them. 

- What would a usual convergence time be for this setup? 
- Is there anything I could do speed this process up? (I tried 
Multipath) 
- Any tips and tricks would be much appreciated 

Thanks in Advance 
-- 
Adam Kajtar 
Systems Administrator 
City of Wadsworth 
akajtar () wadsworthcity org 
----------------------------------------------------- 
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-- 
Adam Kajtar 
Systems Administrator, Safety Services 
City of Wadsworth 
Office 330.335.2865 
Cell 330.485.6510 
akajtar () wadsworthcity org 
----------------------------------------------------- 
http://www.wadsworthcity.com 

Facebook <http://www.facebook.com/cityofwadsworth>* |* Twitter 
<https://twitter.com/CityOfWadsworth> *|* Instagram 
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-- 
Adam Kajtar 
Systems Administrator, Safety Services 
City of Wadsworth 
Office 330.335.2865 
Cell 330.485.6510 
akajtar () wadsworthcity org 
----------------------------------------------------- 
http://www.wadsworthcity.com 

Facebook <http://www.facebook.com/cityofwadsworth>* |* Twitter 
<https://twitter.com/CityOfWadsworth> *|* Instagram 
<https://www.instagram.com/cityofwadsworth/> *|* YouTube 
<https://www.youtube.com/channel/UCymlH-AZgvxTaHtgp3-AmDQ> 


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